FRESNO, Calif. (AP) -- The ex-convict who shot a handful of his co-workers execution-style at a California chicken-processing plant, killing two, kept to himself but was a model employee, according to his boss and neighbors.

Lawrence Nathaniel Jones, 42, had been in and out of prison since 1991 for crimes ranging from armed robbery to a car theft. A neighbor described him as intimidating, but a co-worker and his boss said he was nice and respectful.

As police tried to determine what motivated Jones' attack at the Valley Protein plant in Fresno on Tuesday, those who knew him painted a conflicting portrait of a man who had a history of mostly non-violent crime but appeared, at least outwardly, to have straightened out his life.

Armed with a handgun, he moved methodically among his first three victims a few hours into his morning shift, placing the gun against their head or neck and then pulling the trigger, authorities said.

He shot a woman who tried to flee, and then put the gun to one more person's head and pulled the trigger, but the gun was out of bullets, according to police.

Bob Coyle, president and owner of Valley Protein, said Jones was then confronted by one of the plant's managers. He left the building, reloaded, and shot himself to death.

At least his first three victims appeared not to know what was going on. Police said the gunshots were drowned out by the machinery and ear protectors used by the workers who dice, slice, grind and cook chicken.

Company managers said they and the employees were still puzzled over what went wrong. On Wednesday, the plant remained closed and the company brought in grievance counselors for employees, some of whom walked out wiping away tears and hugging each other.

"Nothing seemed out of the ordinary that day, or any day," Coyle said employees told him. "There were no arguments that ensued, nothing that led up to it. It's a horrific, random act of violence."

Coyle said Jones never showed any signs of trouble, was always respectful and on time. He was recently given a perfect attendance award.

"He was a good employee. Never missed a day, never late. He would say, `Hi Bob. ... I'm blessed to be here.' That's how he'd say things," Coyle said. "He kept to himself, he was quiet, but he got things done."

Michelle Coyle, the company's co-owner and head of human resources, said managers were well aware of Jones' record and prison time. But Jones came highly recommended from a placement agency, she said.

"He was top of the list," Michelle Coyle said. "We knew he did not have a violent criminal past. We try to give people a second chance at life."

Jones, who had worked at the plant for 14 months, had an extensive criminal history dating back to 1991, authorities said. In 1994, he was sentenced to 13 years in prison for robbery, then released on parole in 2001, according to the California Department of Corrections and Rehabilitation.

Jones had also served time for robbery and, later, for vehicle theft and other convictions. He was last paroled in June 2011, the department said.

"He was reviewed and he had not had any violations and so he was discharged from parole" this past May, said department spokesman Luis Patino.

It's common that a condition of being discharged from parole is having a job, he said.

"We want to make sure they can reintegrate into society and support themselves," Patino said.

Police said Wednesday they still had not established a motive and had no more information to release.

Neighbors at the apartment building where Jones lived told the Fresno Bee he had been there for only a few months and usually did not speak to anyone.

"He never smiled or even looked at you. He was intimidating," said Manny Anguiano, who lived two doors down from Jones. "He just rode in on his bike and rode out."

Manuel Verdin, 34, and Salvador Diaz, 32, were killed in the shooting. Arnulfo Conrriguez, 28, was shot in the neck and was listed in critical condition Wednesday at Fresno's Community Regional Medical Center, a hospital spokeswoman said.

Bob Coyle, the company owner, said Diaz started working at Valley Protein in June, while the two other victims started last Wednesday.

Fatima Lopez, 32, the woman who witnessed the slayings and was shot as she started to run, was treated and released.

The Associated Press was unable to reach family members of Jones and the victims.

The U.S. Department of Agriculture inspected the plant after the shootings and gave the go-ahead for the company to reopen on Thursday, Bob Coyle said.

PREVIOUS STORY:Police say three people are dead and another injured after a co-worker opened fire Tuesday at a food service company in Fresno, California.

Police say the suspect, identified as Lawrence Jones, shot himself in the head later outside the building. He later died.

The shooting occurred at the Apple Valley Farms plant in the central part of the city.

Apple Valley Farms, Inc. is a food service equipment company that was established in 2005, according to online business records. A call to the company went to a voicemail recording that said "due to an emergency we are closed for the day."

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